1. Field of the Invention
This invention relates to the art of detection of the interface between coal and shale, and particularly to a mechanized system of detection.
2. General Description of the Prior Art
As found, coal generally lies in seams of varying height with top and bottom interfaces with shale on top and clay on the bottom. In mining the coal, it is thus important to be able to operate coal cutting machines so that cuts are made which just extend to, but not into, the shale; otherwise, all of the coal that could be mined will not be mined (if the cut falls short of the interface), or shale will be mined along with the coal (if the cut goes beyond the interface), and the quality of the coal will be adversely affected. For these reasons, it is highly desirable that coal-shale interfaces be determined with considerable accuracy. Up until now, the identification of floor-ceiling material has been by the natural senses, i.e., seeing, hearing and/or feeling, of a miner standing close to the cutting machine. Not only is this dangerous, but because of the severe environment, the sensitivity of one's natural senses of observation are not particularly keen or reliable.
Accordingly, it is the object of this invention to eliminate the necessity of personal observation of ceiling and floor material of a coal shaft in the vicinity of a coal cutting machine and to accomplish identification of the material by an electromechanical system which can perform the identification with improved accuracy.